(a) Field of the Invention
The present invention relates to a pair of effort-saving looping shears for trimming twigs and branches, and more particularly to one that allows easy grip of its handles at optimal angle.
(b) Description of the Prior Art
Most of the conventional crocodile shears (10) for gardening purpose are comprised of a fixed jaw (101) pivoted to a mobile jaw (102) as illustrated in FIG. 1 with the blade of the mobile jaw (102) practically doing all the trimming. However, said crocodile shears (10) is not provided with an effort-saving mechanism, the user has to grip onto both handles of the crocodile shears and open them up to the maximal degree before executing any trimming, which becomes tiresome and does not meet ergonomics.
An improved design of the crocodile shears (20) provided with an effort-saving mechanism (according. to U.S. Pat. No. 5,689,888) as illustrated in FIG. 2 essentially relates to one that has multiples of toothed sector (203) on the outer side of a fixed jaw (201) with a handle (204) and a mobile jaw (202) being separately pivoted, another toothed sector (205) engaging the toothed sector (203) for both toothed sectors (203)(205) to achieve effort-saving purpose in applying the gardening crocodile shears. However, no substantial effort-saving is achieved by the structure comprised of said toothed sectors (203) (205) for merely relying upon the engagement between them and both handles must be opened up to approximately 180 degrees before executing the cutting and making it difficult to apply the force to close in the handles. That is, said effort-saving mechanism again does not meet ergonomics for failing to provide the optimal angle for force application by both arms of the user.
Another improvement for effort-saving mechanism(30),(e.g. ROC Publication No. 264606) as illustrated in FIG. 3 includes a fixed jaw (301), a mobile jaw (302), handles (303)(304) and a link (305). Wherein, a row of ratchet (3021) is provided on the lower arm of the mobile jaw (302) to be pivoted to the link (305) to the handle (304) by insertion of a pin (306) so that by adjusting the position of the pin (306) to engage the ratchet (3021) to achieve the effort-saving purpose. However, while working, it takes to gradually adjust the engagement position for said pin (306) in the ratchet (3021) and the chance of having skipped or stuck ratchet is considerably high. Particularly, usually the engagement position forthwith skips from the last tooth to the first tooth of the ratchet (3021) as the motion of the link (305) is subject to pull by a coil (307). Again, the improvement does not meet ergonomics by failing to allow control wherein the force can be comfortably applied.
To correct those defects described above, the prevent invention comprised of a strike jaw, a blade jaw, a pivot and an effort-saving mechanism by having said pivot provided with a ratchet that synchronously turns with the blade piece of the blade jaw, a mobile tab being provided to a handle, said mobile table being engaged to the ratchet in a direction adjustable for the user to open up both handles for an optimal angle to repeat applying the force as desired to trim twigs and branches with comfort.
The primary purpose is to provide a structure of effort-saving looping shears for gardening purpose by the engagement of a ratchet and a mobile tab to repeat opening up both handles to an optimal degree meeting ergonomics for applying the force for a comfortable trimming.